<template>
    <view>
        <!-- 使用自定义的搜索组件 -->
        <!-- 动态绑定自定义增强属性 :radius='16'搜索框圆角-->
        <my-search :radius='16' @myclick="gotoSearch"></my-search>        
       <view class="scroll-view-container">
           <!-- 左侧的滑动区域 -->
           <scroll-view class="left-scroll-view" scroll-y="true" :style="{height:wh+'px'}" >
               <block v-for="(item,i) in cateList" :key="i">
                   <!-- 动态绑定属性值,如果索引i=active两项都有,否则第一项 -->
                   <view :class="['left-scroll-view-item',i===active ? 'active' : '']"
                   @click="activeChanged(i)">{{item.cat_name}}</view>
                   <!-- 绑定点击事件,为active赋值 -->
               </block>
               
               
           </scroll-view>
           <!-- 右侧的滑动区域 -->
           <scroll-view scroll-y="true" :style="{height:wh+'px'}" :scroll-top="scrollTop">             
               <view class="cate-lv2" v-for="(item2,i2) in cateLevel2" :key="i2">
                   <!-- 二级分类标题 -->
                   <view class="cate-lv2-title">/ {{item2.cat_name}} /</view>
                   <!-- 二级分类下的三级分类列表 -->
                   <view class="cate-lv3-list">
                       <!-- 三级分类item项 -->
                       <view class="cate-lv3-item" v-for="(item3,i3) in item2.children" :key="i3" @click="gotoGoodsList(item3)">
                           <!-- 三级分类的图片 -->
                           <image :src="item3.cat_icon || defaultPic" ></image>
                           <!-- 三级分类的文本 -->
                           <text>{{item3.cat_name}}</text>
                       </view>
                       
                   </view>
               </view>
               
           </scroll-view>
       </view> 
    </view>
</template>

<script>
    import badgeMix from "@/mixins/tabbar-badge.js"
    export default {
        //将badgeMix混入到当前的页面中进行使用
        mixins:[badgeMix],
        data() {
            return {
                //初始化当前设备可用的高度
                wh:0,
                cateList:[],
                //设置默认选中项
                active:0,
                //二级分类数组
                cateLevel2:[],
                //滚动条距顶部的距离
                scrollTop:0,
                defaultPic:"https://img3.doubanio.com/f/movie/8dd0c794499fe925ae2ae89ee30cd225750457b4/pics/movie/celebrity-default-medium.png"
            };
        },
        onLoad(){
            //调用接口获取当前设备可用的高度赋值给wh
           const sysInfo=uni.getSystemInfoSync()
           //console.log(sysInfo.windowHeight)
           //剩余高度再减搜索框高度50
           this.wh=sysInfo.windowHeight-50
           
           this.getCateList()
        },
        methods:{
            //获取分类列表数据:
            async getCateList(){
                const {data:res}=await uni.$http.get("/api/public/v1/categories")
                if(res.meta.status!==200) return uni.$showMsg()
                this.cateList=res.message
                
                //为二级分类赋值
                this.cateLevel2=res.message[0].children
                // console.log(this.cateList)                
            },
            //点击事件:把i赋与active
            activeChanged(i){
                this.active=i
                
                //重新为二级分类赋值
                this.cateLevel2=this.cateList[i].children
                
                //每次点击后就把scroll-top切换为0或1像素
                this.scrollTop=this.scrollTop ? 0 : 1                                
            },
            //跳转到商品列表页面:
            gotoGoodsList(item3){
                uni.navigateTo({
                    url:"/subpkg/goods_list/goods_list?cid="+item3.cat_id
                })
            },
            gotoSearch(){
                uni.navigateTo({
                    url:"/subpkg/search/search"
                })
            }
        }
    }
</script>

<style lang="scss">
.scroll-view-container{
    display: flex;
}

.left-scroll-view{
    width: 120px;
}

.left-scroll-view-item{
    background-color: #e6e6e6;
    line-height:60px;
    text-align: center;
    font-size: 12px;
    
    &.active{ //既有.left-scroll-view-item,又有.active激活项
       background-color: #FFFFFF; 
       position: relative;
       
       &::before{
           content:" ";
           display: block;
           width: 3px;
           height: 30px;
           background-color: #c00000;
           position: absolute;
           top:50%;
           left:0;
           transform: translateY(-50%);
       }       
    }           
}
.cate-lv2-title{
    font-size: 12px;
    font-weight: bold;
    color: #ff0000;
    text-align: center;
    padding: 15px 0;
} 

.cate-lv3-list{
    display: flex;
    flex-wrap: wrap;
    .cate-lv3-item{
        width: 33.33%;
        display: flex;
        flex-direction: column;
        justify-content: center;
        align-items: center;
        margin-bottom:10px ;
        image{
            width: 60px;
            height: 60px;}
        text{
            font-size: 12px;
        }
    }
}
</style>
